This invention relates to a novel S-methyl N-[{N-methyl-N-(N,N-disubstituted aminosulfenyl)carbamoyl}-oxy]thioacetami date derivative, an insecticidal, miticidal or nematocidal composition containing the derivative as an active ingredient, a process for preparing such a derivative, and a method for controlling noxious insects, mites or nematodes. In the present specification, the term "insecticidal" includes "miticidal" and "nematocidal" in addition to "insecticidal," and the term "insect(s)" includes "mite(s)" and "nematode(s)" in addition to "insect(s)", respectively, unless otherwise indicated.